Basic operation of electrosprays is well-known and characterized in a large number of publications and used in many applications. Most of these applications are distinguished by relatively short-duration operation, especially where the electrospray is emitted through one or more apertures in grids composed of some solid material. During electrospray operation, and particularly during startup or with certain applied voltages and/or liquid flowrates applied to the electrospray, the electrospray may deposit some amount of sprayed liquid upon the solid edges of the grids (overspray), especially proximate the aperture. Accumulated build-up of this deposited liquid adversely impacts performance of electrospray operation over time, particularly when low vapor pressure liquids are used. Because this accumulation is gradual and most applications are short-duration, performance impacts had been negligible and no solutions to liquid accumulation had been sought.
For extended electrospray operation e.g. for durations exceeding 100 hours, or for particular operating conditions, no effective means for transport/removal of accumulated liquid exists. Consequently, duration of electrospray operation is limited to the point where the accumulated liquid interferes with, and ultimately prevents, proper function. Proper function is restored by performing manual cleaning of accumulated liquid and/or replacement of affected components.
Frequent cleaning or replacement of components is costly, and for applications where cleaning or replacement is impossible, the duration of electrospray operation is limited to the time it takes for some critical buildup preventing proper operation.